The goal of this research program is to evaluate new biologic functions of parathyroid hormone related peptide (PTHrP). This will be accomplished by evaluating the biologic activities of parathyroid/parathyroid related peptide (PTH/PTHrP) in vivo in C57 BL-6 mice. The effect of selected PTH/PTHrP agonists and antagonists will be evaluated on the: 1) induction of anagen hair growth in telogen mice, 2) inhibition of catagen hair maturation in anagen mice, and 3) maintenance of anagen hair growth in anagen mice. The second goal of this research program is to evaluate the biologic activity and mechanism of action of PTH/PTHrP agonists and antagonists on hair growth in cultured hair follicles and in organ hair cultures from C57 BL-6 mice, PTHrP knockout mice, PTHrP receptor knockout mice and their normal litter mates.